RT Journal Article T1 Mapping Cropland Intensification in Ecuador through Spectral Analysis of MODIS NDVI Time Series A1 Recuero, Laura A1 Maila, Lilian A1 Cicuéndez, Víctor A1 Sáenz, César A1 Litago, Javier A1 Tornos, Lucía A1 Merino de Miguel, Silvia A1 Palacios Orueta, Alicia AB Multiple cropping systems constitute an essential agricultural practice that will ensure food security within the increasing demand of basic cereals as a consequence of global population growth and climate change effects. In this regard, there is a need to develop new methodologies to adequately monitor cropland intensification. The main objective of this research was to assess cropland intensification by means of spectral analysis of MODIS NDVI time series in a high cloudiness tropical area such as Ecuador. A surface of 89,225 ha of the main staple crops in this country, which are rice and maize crops, was monitored to assess the evolution of the number of crop cycles. The 20-year period of NDVI time series was used to calculate the periodograms across four subperiods (2001–2005, 2006–2010, 2011–2015, 2016–2020). The maximum ordinate value of each periodogram was used as an indicator of the number of growing crop cycles per year identifying single-, double-, and triple-cropping systems in each subperiod. Cropland intensification was assessed by comparing the cropping system between the subperiods. Results reveal that more than half of the studied croplands experienced changes in the cropping systems, and 40% showed positive trends in terms of the number of growing crop cycles, being principally located near the main rivers where irrigation facilitates crop development during the dry season. Therefore, the area under single cropping decreased from over 60,000 ha in the first subperiod to less than 50,000 ha in the last two subperiods. The cropland surface subjected to multi-cropping practices increased during the second decade of the study period, with a double-cropping system being more widely used than growing three crops per year, reaching surfaces of 24,400 ha and 10,450 ha in the last subperiod, respectively. The robust results obtained in this research show the great potential of the periodogram approach for the discrimination of cropping systems and for mapping intensification areas in tropical regions where dealing with noisy remote sensing time series as a consequence of high cloudiness is a great challenge. PB MDPI YR 2023 FD 2023-09-06 LK https://hdl.handle.net/20.500.14352/104024 UL https://hdl.handle.net/20.500.14352/104024 LA eng NO Recuero, L.; Maila, L.; Cicuéndez, V.; Sáenz, C.; Litago, J.; Tornos, L.; Merino-de-Miguel, S.; Palacios-Orueta, A. Mapping Cropland Intensification in Ecuador through Spectral Analysis of MODIS NDVI Time Series. Agronomy 2023, 13, 2329. https://doi.org/10.3390/ agronomy13092329 Academic Editors: Riccardo NO 2022Descuento MDPI NO Ministerio de Ciencia, Innovación y Universidades NO European Commission NO Universidad Politécnica de Madrid NO Secretaría de Educación Superior, Ciencia, Tecnología e Innovación (Ecuador) NO Comunidad de Madrid DS Docta Complutense RD 10 abr 2025